The present invention relates to window frame construction, and more specifically to window frame members having channels for accepting and covering siding or sheathing attached to the exterior surface of a building structure.
Many window frames and frame members are prefabricated. These window frames and frame members are often constructed from vinyl, aluminum, or composite materials. The window frames are typically installed during new construction of a building, such as a house, or during replacement of existing windows.
During new construction, a window frame is normally installed within a rough opening formed within and defined by the frame of a building structure. Typically, a window frame used in new construction applications includes a nailing flange extending radially from the window frame and around the rough opening. During installation, nails, staples or other fastening means are used to secure the nailing flange, and thus the window frame, to the plywood sheathing of the building.
Replacement window frames are often installed over an existing window frame of a building, either during renovation of the structure or during replacement of the structure""s windows. The existing window is first removed, and the remaining window frame is prepared for installation of the replacement window frame. The existing frame is usually constructed from wood or from a metal, such as aluminum. Alternatively, the existing window and its frame may be removed, thereby leaving a rough opening in the building structure. This rough opening is then prepared to accept the replacement window frame.
Preparation of the existing frame or rough opening includes several steps, such as removing chips and rough edges in existing wooden window frames, fastening wood blocks into the sash track of an existing metal frame sill component to help support the weight of the new window, or cleaning and checking a rough frame opening for squareness. The replacement window frame is often secured by driving screws through pre-drilled holes in the interior of the replacement window frame and into the existing frame or rough opening.
A replacement window frame may include a flange, often called a flush fin, that extends radially from the window frame and around the exterior of the window frame opening after installation. The flush fin conceals any gaps created during preparation of the existing window frame or any damaged areas surrounding the window frame or rough opening. Flush fin window designs are often used when replacing window frames in buildings having stucco exteriors. The nuances of new construction and replacement window installation are generally known to window frame installers in the industry and may be found in installation instruction workbooks and manuals published by window frame manufacturers.
The design of a window frame member, such as a picture window frame member, double-hung window frame member or awning window frame member, to name a few, varies according to the particular end use application, i.e., the type of installation for which the frame member, and consequently the assembled frame, will be used. For example, a window frame member may have a nailing flange if it is to be used in a new construction application. This same jamb may also have a flange or flanges used to create a conventional J-channel for accepting or covering siding or sheathing that is attached to a building structure. The window frame member may also have no flanges or a flush fin flange, for example, if it is intended for use in a replacement window frame. Different designs for the same window frame member, therefore, are used for different applications.
Prefabricated window frame members are often formed from a material such as vinyl or polyvinyl chloride (PVC) using extrusion processes. Molten metal or plastic is forced, drawn or extruded through a die for shaping into window frame members. The die is usually made from a material such as brass. In order to manufacture the different designs of a window frame member for use in the aforementioned different applications, each design is created using a different die in the extrusion process. Alternatively, a single die having additional die plates is used to create the different designs. After extrusion, the extruded window frame member continues to a cooling tank section or calibrator where it is reshaped and cooled in order to harden the member. The member may then be cut into usable or transportable lengths of window frame member. The details of extrusion, reshaping and cooling are know in the art and are disclosed, for example, in Engineered Materials Handbook, Volume 2, Engineering Plastics, Robert L. Miller, xe2x80x9cThermoplastic Extrusion,xe2x80x9d pp. 378-88.
The aforementioned manufacturing technique, however, has several disadvantages. First, dies are very expensive, often costing several hundred thousand dollars. Therefore, the use of multiple dies or additional die plates greatly compounds manufacturing costs. Also, the use of multiple dies requires either longer production lines or multiple production lines, resulting in increased operating costs as well as increased space consumption.
As mentioned, window frame members are sometimes manufactured with J-channels formed integrally therewith or as attachable accessories. These J-channels are constructed to accept a siding or sheathing product attached to the building structure and to partially cover the siding or sheathing. The sheathing or siding is generally constructed from aluminum or vinyl. The J-channel of a jamb member is constructed to cover the ends of the siding or sheathing. The J-channel is usually constructed with sufficient depth to adequately cover the ends of the siding or sheathing during expansion and contraction resulting from temperature changes. The J-channels also help to exclude water from the siding or sheathing and to cover misalignments of the ends of the sheathing or siding. It has been found that a channel of approximately 0.750 inch is normally sufficient to cover the ends as the sheathing or siding expands or contracts. It should be apparent that the J-channel of a header or a sill member covers the bottom or top, respectively, of siding or sheathing that is attached to a building structure.
Conventional J-channels are usually formed such that they extend from the wall-facing side of a frame or frame member, that side of the window frame facing the opening in a building that accepts the window frame and opposite the window supported by the frame. The J-channel generally has a return flange extending from the wall facing-side, typically 0.75 inch in length, that covers the ends of the siding or sheathing attached to the structure. The J-channel is formed from a nailing flange extending from the wall-facing side, a projection portion extending away from the nailing flange portion in a direction usually normal to the nailing flange portion, and the return portion connected to the projection portion and disposed opposite and parallel to the nailing flange portion. This configuration creates a substantially rectangular channel that has a longitudinal opening for receiving the free end of a siding or sheathing panel. The nailing flange typically extends one inch past the return flange (i.e., the nailing flange extends 1.75 inches from the wall facing side) in order to allow sufficient room to attach the flange, usually by a series of nails, to the structure. Window frame members with J-channels such as that described above are disclosed in U.S. Pat. No. 5,392,574 to Sayers and U.S. Pat. No. 5,660,010 to Sayers.
The aforementioned J-channel design, however, creates several problems. First, the J-channel design increases the xe2x80x9csight-linexe2x80x9d of the frame member by about 0.75 inch, and thereby decreases the attractiveness of the window frame. The frame member xe2x80x9csight-linexe2x80x9d for purposes of this application is defined as the visible width of the frame member as viewed from the exterior of the building structure. It has been recognized that a more attractive frame member has a reduced xe2x80x9csight-linexe2x80x9d because the ratio of visible window to visible frame increases as the sight-line decreases. Also, significant expenses are incurred during manufacturing a window frame member having a conventional J-channel because additional materials are required to form the J-channel""s return flange, nailing flange, and projection portion. This is particularly true if a plastic extrusion process is utilized to manufacture the window frame member because approximately one half of the costs of producing plastic extrusions can be attributed to the raw materials, such as polyvinyl chloride resin.
Therefore, there is presently a need for a new method of creating frame members that have varied end use applications from a single die plate. Further, there is presently a need for an aesthetically pleasing and cost effective window frame member that can effectively conceal portions of a siding or sheathing product attached to a building.
As herein described, the present invention is a window frame member for inclusion in a window frame assembly. The window frame assembly receives at least one window and is configured for fixedly mounting in an opening in a wall of a structure. The structure has an interior wall and an exterior wall. The window frame member is defined by an interior surface disposed proximate to the interior wall when the window frame assembly is mounted, a window-facing side disposed to engage the window and a wall-facing side disposed opposite the window facing-side. The window frame member comprises a channel formed within the frame member. The channel is contained within the cross-sectional area defined by the interior and exterior surfaces and the window-facing and wall-facing sides. The channel is capable of accepting an edge of an exterior siding or sheathing product attached to the structure, the edge being at least partially covered by the channel during expansion and contraction of the same, for example, during extreme temperature changes. The present invention may further comprise a first flange portion extending radially outward from the wall-facing side.
The new window frame member construction provides several benefits over prior window frame member designs that include J-channels. First, the design provides for a reduced sight-line because at least part of the channel that accepts an edge of an exterior siding or sheathing product is contained within the frame member itself. Also, by including at least part of the channel within the frame member, and preferably using existing walls within the frame cross-section itself for part of the J-channel construction, less resin is needed to create each window frame member. The second flange portion may either be shortened or eliminated, depending upon the depth of the channel. Further, the length of any nailing flange decreases along with corresponding reductions in the length of the second flange portion. It should be apparent that any conservation in material expenditures on a production line leads to significant manufacturing cost savings and competitive advantages.